Genetic Armor in Flu Season

Editor’s note: Pending an FDA decision, 23andMe no longer offers new customers access to health reports referred to in this post. Customers who received their health information prior to November 22, 2013 will still be able to see their health reports, but those who purchased after that time will only have access to ancestry information as well as access to their uninterpreted raw data. These new customers may receive health reports in the future dependent on FDA marketing authorization.

A sure way to make you more diligent about washing your hands is to read a little coverage on what’s turning out to be the worst flu season in recent memory.

A lucky few of us, however, have defenses that go beyond trusty soap and water — our genes. Approximately 30 percent of people with European ancestry and 20 percent of those with African ancestry carry a mutation that gives them extra protection against the most common strains of norovirus. Norovirus is one of the three flu or flu-like viruses now spreading across the globe during this sick season.

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What is making this so bad is what the New York Timesdescribes as “the convergence of three flu or flu-like epidemics” hitting all at once. These three illnesses include an unusually virulent flu virus, a pretty nasty norovirus, and a whooping cough outbreak that’s as bad as it’s been in 60 years. As the article indicates, this is all happening “amid the normal winter highs for the many viruses that cause symptoms on the colds and flu spectrum.” Not a pretty picture for those who fret about getting ill.

The Centers for Disease Control (CDC) is a little less breathless in its description of the flu season, but officials there are still heralding a warning nonetheless.

“Reports of influenza-like-illness (ILI) are nearing what have been peak levels during moderately severe seasons,” according to the CDC’s Dr. Joe Bresee. The CDC continues to recommend flu shots as well as antiviral medication when appropriate.

So let’s zero in on the norovirus, which is sometimes described as the “stomach flu.” In reality, it isn’t the flu, but “viral gastroenteritis.” This nasty bug is hugely contagious and pretty unpleasant with symptoms that include abdominal pain, vomiting and diarrhea. It spreads quickly, especially in close quarters and can rapidly rip through schools, retirement communities and hospitals. This latest outbreak is hitting the US right as the flu is spreading. And this particular strain hit England a few weeks ago, making more than a million people ill, according to the Guardian.

Some people, however, may be safer than most during this time of illness. About 30 percent of people with European ancestry and about 20 percent of those with African ancestry carry the AA version of SNP rs601338 in the FUT2 gene. For these lucky folks need not fear the most common strain of norovirus like the rest of us. They lack the molecules noroviruses use to enter the digestive tract cells. It doesn’t mean they are bulletproof from getting sick, but they are protected against most strains of norovirus. Unfortunately, very few people of Asian ancestry carry the resistant genetic variant.

Whether you belong to the fortunate ones who carry this extra genetic protection or not, it is still a good idea to keep washing those hands. If you haven’t already you also might consider getting a flu shot if available.

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